This invention relates to a process and apparatus for controlling the flow of a refrigerant in countercurrent heat exchange with a stream being cooled.
Although the invention is applicable broadly, it finds particular utility in processing raw natural gas. In the gathering of such raw natural gas it is frequently expedient to process relatively small volumes, for example in the neighborhood of 1 to 25 million standard cubic feet per day (MMSCFD) which is about 0.03- 0.80 m.sup.3 /s in the field. Such processing may often include steps of phase separation, compression, and heat exchange.
It is desirable that such facilities be maintained simple and straightforward in operation so that they can operate with a minimum of maintenance and operator attention. It is also desirable that such units require a minimum of utility facilities. Where raw natural gas streams are to be cooled it is necessary to take steps to avoid the formation of hydrates which can cause plugging of heat exchangers or other equipment.
An object of the invention is to cool a raw natural gas stream in a simple and straightforward manner. Another object of the invention is to cool a raw natural gas stream for further processing without the formation of hydrates. Another object of the invention is to utilize available refrigeration fully while avoiding hydrate formation with a minimum use of hydrate inhibitor. Another object of the invention is to control the flow of a refrigerant in countercurrent flow with a fluid stream being cooled.